Modifying Crystallographic Orientations of Polycrystalline Si Films Using Ion Channeling

1984 ◽  
Vol 35 ◽  
Author(s):  
K. T-Y. Kung ◽  
R. B. Ivepson ◽  
R. Reif
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Silicon On Insulator ◽  
Furnace Annealing ◽  
Ion Channeling ◽  
Amorphous Substrates ◽  
Pressure Chemical ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTPolycrystalline silicon films 4800 Å thick deposited via low pressure chemical vapor deposition on oxidized silicon wafers have been amorphized by silicon ion implantation and subsequently recrystallized at 700°C. Due to channeling of the ions through grains whose <110> axes were sufficiently parallel to the beam, these grains survived the implantation step and acted as seed crystals for the solid-phase epitaxial regrowth of the film. This work suggests the feasibility of combining ion implantation and furnace annealing to generate large-grain, uniformly oriented polycrystal1ine films on amorphous substrates. It is a potential low-temperature silicon-on-insulator technology.

Polycrystalline Silicon Films Formed by Solid-Phase Crystallization of Amorphous Silicon: the Substrate Effects on Crystallization Kinetics and Mechanism

1996 ◽  
Vol 424 ◽  
Author(s):  
Y.-H. Song ◽  
S.-Y. Kang ◽  
K. I. Cho ◽  
H. J. Yoo ◽  
J. H. Kim ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Crystallization ◽  
Substrate Effects ◽  
Random Nucleation ◽  
Pressure Chemical ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
Induced Crystallization

AbstractThe substrate effects on the solid-phase crystallization of amorphous silicon (a-Si) have been extensively investigated. The a-Si films were prepared on two kinds of substrates, a thermally oxidized Si wafer (SiO2/Si) and a quartz, by low-pressure chemical vapor deposition (LPCVD) using Si2H6 gas at 470 °C and annealed at 600 °C in an N2 ambient for crystallization. The analysis using XRD and Raman scattering shows that crystalline nuclei are faster formed on the SiO2/Si than on the quartz, and the time needed for the complete crystallization of a-Si films on the SiO2/Si is greatly reduced to 8 h from ˜15 h on the quartz. In this study, it was first observed that crystallization in the a-Si deposited on the SiO2/Si starts from the interface between the a-Si film and the thermal oxide of the substrate, called interface-induced crystallization, while random nucleation process dominates on the quartz. The very smooth surface of the SiO2/Si substrate is responsible for the observed interface-induced crystallization of a-Si films.

Grain size, Grain Uniformity, and (111) Texture Enhancement by Solid-phase Crystallization of F- and C-implanted SiGe Films

2000 ◽  
Vol 15 (7) ◽  
pp. 1630-1634 ◽  
Author(s):  
A. Rodríguez ◽  
J. Olivares ◽  
C. González ◽  
J. Sangrador ◽  
T. Rodríguez ◽  
...  
Keyword(s):  
Grain Size ◽  
Vapor Deposition ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Crystallization ◽  
Grain Sizes ◽  
Pressure Chemical ◽  
Film Microstructure ◽  
Si Films ◽  
Size Dispersion

The crystallization kinetics and film microstructure of poly-SiGe layers obtained by solid-phase crystallization of unimplanted and C- and F-implanted 100-nm-thick amorphous SiGe films deposited by low-pressure chemical vapor deposition on thermally oxidized Si wafers were studied. After crystallization, the F- and C-implanted SiGe films showed larger grain sizes, both in-plane and perpendicular to the surface of the sample, than the unimplanted SiGe films. Also, the (111) texture was strongly enhanced when compared to the unimplanted SiGe or Si films. The crystallized F-implanted SiGe samples showed the dendrite-shaped grains characteristic of solid-phase crystallized pure Si. The structure of the unimplanted SiGe and C-implanted SiGe samples consisted of a mixture of grains with well-defined contour and a small number of quasi-dendritic grains. These samples also showed a very low grain-size dispersion.

Ar+ Implantation Effects on Polycrystalline Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
J. H. Lee ◽  
C. W. Hwang ◽  
J. E. Shin ◽  
Y. S. Jin ◽  
S. B. Mah
Keyword(s):  
Solid Phase ◽  
Chemical Vapor ◽  
Implantation Dose ◽  
Structural Deformation ◽  
Implantation Technique ◽  
Polycrystalline Thin Films ◽  
Average Grain Size ◽  
Pressure Chemical ◽  
Thin Polycrystalline ◽  
Si Films

AbstractThe solid phase crystallization behavior of argon ion (Ar+) implanted very thin polycrystalline silicon (poly-Si) films has been investigated. Poly-Si films of 500Å thickness were deposited at 625°C by low pressure chemical vapor deposition (LPCVD). The films were amorphized by Ar+ implantation with 7 ° tilt angle. The amount of ions implanted was varied from 2.0 × 1013 cm-2 to 1.2 × 1015 cm-2 and the acceleration voltages from 40KeV to 120KeV. The films were recrystallized by furnace annealing at 580°C for 48 hours in N2 atmosphere, followed by 1000°C annealing The crystallinity of the recrystallized Si films and the distribution of the argon atoms in the film were investigated. It was found that the crystallinity strongly depended on the Ar+ implantation dose. The average grain size of Ar+ implanted film was about 0.25μm, which was smaller than that of Si+ implanted film of the same dose, 0.45μm. Ar atoms retarded the grain growth rate during the annealing process and the excess Ar atoms in Si films were segregated at the surface of silicon films after 1000°C annealing Poly-Si thin film transistors (TFTs) were fabricated at high temperature using Ar+ implantation technique. Remarkable electrical characteristics (Ids- Vgs) were obtained such as an electron mobility of 35 cm2/V.s, which was attributed to the enhancement of crystallinity by Ar+ implantation. But, segregated Ar atoms near the interface would give rise to structural deformation and crystalline defects which can act as the scattering and’ trapping centers for carriers.

Fabrication of Si-Gate CMOS Devices In A Heteroepitaxial Si/Caf2/Si Structure

1987 ◽  
Vol 91 ◽  
Author(s):  
Hiroshi Onoda ◽  
Masayoshi Sasaki ◽  
Teruo Katoh ◽  
Norio Hirashita
Keyword(s):  
High Speed ◽  
Solid Phase ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
Cmos Inverter ◽  
Ion Channeling ◽  
Propagation Delays ◽  
Segregation Effect ◽  
Recent Developments ◽  
Si Films

ABSTRACTThe results of recent developments on device fabrication in a heteroepitaxial Si/CaF2/Si structure have been presented and discussed. A high quality heteroepitaxial Si/CaF2/Si structure has been obtained by successive molecular beam epitaxy of CaF2 and Si. The epitaxial Si film on CaF2/Si structure has an ion channeling minimum yield of 7 %. It was found, however, that Ca and F segregated at the surface of epitaxial Si films. A possibility of reducing the segregation effect by the use of solid phase epitaxy of Si has been proposed.Si-gate CMOS devices have been successfully fabricated in a Si/CaF2/Si structure with alt improved CMOS proress. The maximum effective mobiliiies are about 570 cm2/V.sec and 240 cm2/V.sec for n-channel and p-channel transistors, respectively. Propagation delays below 360 ps have been obtained for CMOS inverter chains with Leff = 2 μm. These results indicate that the Si/CaF2/Si structure has potential for the fabrication of high-speed silicon-on-insulator devices.

Effects of Deposition Parameters on Crystallization of Pecvd Amorphous Silicon Films

1995 ◽  
Vol 403 ◽  
Author(s):  
Yaozu Wang ◽  
Reece Kingi ◽  
Osama O. Awadelkarim ◽  
Stephen J. Fonash
Keyword(s):  
Grain Size ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Precursor Film ◽  
Furnace Annealing ◽  
Glass Substrates ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Si Films

AbstractPlasma-enhanced chemical vapor deposition was used to deposit a-Si:H thin films (∼ 1000 Å) at various temperatures below 300°C on Coming 7059 glass substrates using a silane-based plasma. These films were used as precursor materials to produce solid phase crystallized polycrystalline silicon (poly-Si) by conventional furnace annealing at 600°C in N2 ambient. The precursor a-Si and final poly-Si films were examined using spectroscopic ellipsometry and transmission electron microscopy. Precursor film deposition temperatures were found to affect the void density in the a-Si film and grain size in the resulting poly-Si film with lower deposition temperatures leading to higher void density in the a-Si film and larger grain size in the poly-Si film.

Stress Induced During the Solid-phase Crystallization of Amorphous Silicon Deposited by LPCVD

1995 ◽  
Vol 403 ◽  
Author(s):  
T. Mohammed-Brahim ◽  
K. Kis-Sion ◽  
D. Briand ◽  
M. Sarret ◽  
F. Lebihan ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Solid Phase ◽  
Chemical Vapor ◽  
In Situ Monitoring ◽  
Crystallization Time ◽  
Solid Phase Crystallization ◽  
Pressure Chemical ◽  
Hall Effect Measurements ◽  
Deposition Techniques

AbstractThe Solid Phase Crystallization (SPC) of amorphous silicon films deposited by Low Pressure Chemical Vapor phase Deposition (LPCVD) using pure silane at 550'C was studied by in-situ monitoring the film conductance. The saturation of the conductance at the end of the crystallization process is found transient. The conductance decreases slowly after the onset of the saturation. This degradation is also observed from other analyses such as ellipsometry spectra, optical transmission and Arrhenius plots of the conductivity between 250 and 570K. Hall effect measurements show that the degradation is due to a decrease of the free carrier concentration n and not to a decrease of the mobility. This indicates a constant barrier height at the grain boundaries. The decrease of n is then due to a defect creation in the grain. Hence, whatever the substrate used, an optimum crystallization time exists. It depends on the amorphous quality film which is determined by the deposition techniques and conditions and on the crystallization parameters.

scholarly journals Formation of Buried Epitaxial Si-Ge Alloy Layers in Si Crystal by High Dose Ge ION Implantation

1991 ◽  
Vol 235 ◽  
Author(s):  
Kin Man Yu ◽  
Ian G. Brown ◽  
Seongil Im
Keyword(s):  
Ion Implantation ◽  
Single Crystal ◽  
Lattice Mismatch ◽  
Solid Phase ◽  
Metal Vapor ◽  
Ion Source ◽  
Vacuum Arc ◽  
High Dose ◽  
Solid Phase Epitaxy ◽  
Ion Channeling

ABSTRACTWe have synthesized single crystal Si1−xGex alloy layers in Si <100> crystals by high dose Ge ion implantation and solid phase epitaxy. The implantation was performed using the metal vapor vacuum arc (Mevva) ion source. Ge ions at mean energies of 70 and 100 keV and with doses ranging from 1×1016 to to 7×1016 ions/cm2 were implanted into Si <100> crystals at room temperature, resulting in the formation of Si1−xGex alloy layers with peak Ge concentrations of 4 to 13 atomic %. Epitaxial regrowth of the amorphous layers was initiated by thermal annealing at temperatures higher than 500°C. The solid phase epitaxy process, the crystal quality, microstructures, interface morphology and defect structures were characterized by ion channeling and transmission electron microscopy. Compositionally graded single crystal Si1−xGex layers with full width at half maximum ∼100nm were formed under a ∼30nm Si layer after annealing at 600°C for 15 min. A high density of defects was found in the layers as well as in the substrate Si just below the original amorphous/crystalline interface. The concentration of these defects was significantly reduced after annealing at 900°C. The kinetics of the regrowth process, the crystalline quality of the alloy layers, the annealing characteristics of the defects, and the strains due to the lattice mismatch between the alloy and the substrate are discussed.

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